Authors : Adeniyi O. Adesina; Kazeem A. Bello; Lukman A. Animashaun; Adetayo A. Yekinni; Adebola M. Oghene; Ridwan A. Oyetunde

Volume/Issue : Volume 11 - 2026, Issue 6 - June

Google Scholar : https://tinyurl.com/4cbdwu7p

Scribd : https://tinyurl.com/yxcvmerc

DOI : https://doi.org/10.38124/ijisrt/26jun073

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Abstract : Welded interfaces in cast iron, mild steel, and aluminium alloy (AA6063) were characterised through coupled microstructural analysis and coupled thermal–mechanical finite element simulation under three post-weld cooling conditions: natural air cooling, oil quenching, and water quenching. Specimens (200 mm × 100 mm × 12 mm) prepared in single-bevel and double-bevel configurations were welded by Shielded Metal Arc Welding (SMAW). Optical metallography revealed that water quenching promotes martensitic structures in cast iron and mild steel, increasing hardness but severely reducing impact toughness, while air cooling retains ductile ferrite–pearlite matrices. In aluminium, rapid quenching produces finer equiaxed grains with higher dislocation density, improving strength at the cost of ductility. ANSYS Workbench finite element simulations quantified the thermal gradients, residual stresses, and geometric distortions induced by each quenching medium. Water quenching generated the highest residual stresses (320 MPa, 400 MPa, and 150 MPa for cast iron, mild steel, and aluminium respectively) and the greatest distortion. Oil quenching achieved the best balance between stress relief and microstructural refinement. FEA cooling-rate predictions correlated well with experimental microstructural observations, validating the numerical model. Double-bevel joints consistently distributed heat more uniformly than single-bevel configurations, reducing peak residual stresses by up to 12%. These findings provide a systematic, experimentally validated basis for post-weld cooling protocol selection in structural and automotive welding applications.

Keywords : Heat-Affected Zone; Microstructure; Quenching; FEA; Residual Stress; Cast Iron; Mild Steel; Aluminium; Cooling Rate; Distortion; SMAW; Thermo-Mechanical.

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